Several studies had shown that younger breast cancers often exhibited more aggressive biological characteristics, such as estrogen receptor-negative (ER–) and HER2 positive tumor, high grade and are more prone to lymph node metastasis, resulting in higher recurrence and mortality rates.[10–14] Thus, in this study, we used an age cutoff of 40 years to perform the relationship between age and prognosis in her2 positive breast cancer patients. This evidence concerns the gene ERBB2 and breast cancer.